Pipe connection with seal for outboard boat drive unit



Aug. 13, 1968 A. BERGSTEDT PIPE CONNECTION WITH SEAL FOR OUTBOARD BOAT DRIVE UNIT Filed NOV. 29, 1966 INVBNTOR KARL ABDON BERGSTEDT myfiw ATTORNEY United States Patent 3,396,693 PIPE CONNECTION WITH SEAL FOR OUTBOARD BOAT DRIVE UNIT Karl Abrlon Bergstedt, Goteborg, Sweden, assignor to AB Penta, Goteborg, Sweden Filed Nov. 29, 1966, Ser. No. 597,785 Claims priority, application Sweden, Dec. 1, 1965, 15,550/65 14 Claims. (Cl. 115-41) ABSTRACT OF THE DISCLOSURE A pipe connection between a boat and outboard drive power leg is completed through a pipe entering loosely into a chamber. A sealing pad is engaged around the pipe and seals against the face of the chamber due to forward propeller thrust. Upon tilting of the outboard leg, the pipe withdraws from the chamber carrying the sealing pad with it.

In those drive arrangements for boats where the motor is placed inboard and connected to a propeller shaft housing or outboard leg pivoted at the stern of the boat to permit tilting up of the leg, it may be desired to pass the motor exhaust into the propeller housing to be vented into the water, near or through the propeller for effective sound damping. Further, it is usual that the cooling water intake for the motor is arranged on the propeller shaft housing, and a line is run in from the housing to the motor. Because the propeller shaft housing is intended to be tiltable, diffieulties are encountered with the requisite pipe couplings between the boat and the housing, and the object of the invention is to provide a flexible yet tight pipe connection. Such couplings in the prior art have been afforded through flexible accordion hoses, which are bulky, subject to wear, expensive, and otherwise undesirable.

The characteristic feature of the invention is that a fixed or adjustable abutment in the form of a disc, flange or the like is attached near the end of a pipe, that a packing is slipped on the pipe between the end of the pipe and the disc, and that the end of the pipe extends into a chamber. Such pipe and chamber are arranged so that one is a rigid part of or attached to the boat while the other is a rigid part of or attached to the tiltable outboard leg. The wall of the chamber towards the end of the pipe is formed into a stop or abutment normally pressed against the packing by the action of the propeller thrust. In the specific embodiment herein shown and described, the pipe is rigidly connected to the boat and projects aftwardly a short distance from a fixed but adjustable ring, while the chamber comprises a portion of the outboard leg communicating through an opening into said chamber with the aftward open end of the pipe.

The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawing, in which:

FIG. 1 shows a side view, in partial section, of the stern part of a boat with propeller shaft housing installed and a pipe connection according to the invention; and

FIG. 2 shows a view of a packing contained in the pipe connection of FIG. 1.

The boat stern, shown as transom 1, is provided with an opening 2 covered by a closure member or shield 3,

3,396,693 Patented Aug. 13, 1968 or the like, fixed to the outside of the transom and sealed against it around the opening by a gasket 4. The shield 3 carries a vertically tiltable propeller housing 5 which includes an upper end transmission case portion 6 for a bevel gear forward-reverse transmission (not shown). The shaft 7 entering the transmission case and propeller housing is driven by a motor 20 mounted in the stern of the boat by way of a belt or chain 8 passing over a wheel 9 on the said input shaft 7. Between the shield 3 and the transmission case 6, a sealing ring 10 is arranged in which the case may tilt about the axis of shaft 7. Belt 8 is preferably driven in the direction of arrow 21 tending to oppose tilting of the leg 5 when the engine is operating.

The exhaust of the motor is passed through a line 11 to an opening in the shield 3, on the outside of which a pipe end portion or nipple 12 carries the gases into a chamber 13 in the propeller housing 5, whence there is a passage 22 to an exit opening 23 under the surface of the water near the propeller. Alternatively, openings 23 may admit cooling water which may pass through passages 22 and nipple 12 into conduit 11 and thence to the engine. The arrangement of leg 5 including underwater propeller may be as shown in my copending application Ser. No. 471,683, filed July 13, 1965. Inasmuch as the outboard housing is to be capable of swinging up during operation, for example to negotiate shallow water, or whenever the housing encounters any obstacle, the connection between the pipe end portions 12 and the chamber 13 must be loose, i.e. slidably separable, yet at the same time tight under ordinary operation conditions so that fluids will not escape in passing between the pipe and chamber.

This is accomplished by providing a backing plate or ring 14, or the like, slipped on the pipe end portion 12. This plate is in effect a part of the hull, serving as a fixed backing plate, but the plate is preferably adjustable into selected predetermined fixed positions. The plate is provided with abutment means such as one or more stop members 15, each of which as shown comprises a spherical surface cooperating with a setscrew 16 screwed through the shield 3. By adjusting the setscrew 16, it is possible to change the trim of the outboard housing 5. The face or side 24 of the chamber 13 in housing 5 which is disposed towards the pipe nipple 12 is fiat and has an opening 25 for the end of the pipe nipple 12, which opening is of slightly larger diameter than the nipple 12 so that the free end of the nipple will clear the edges of the opening when the housing 5 is tilted up. Between the plate 14 and the wall 24 0f the chamber 13, there is an elastic resilient, compressible packing 17 of rubber, plastic or similar material slipped over the nipple 12, the hole in the packing before installation on the nipple being somewhat smaller in diameter than the nipple 12, so that the packing 17 must be forced onto the nipple and is retained by its resilience or elasticity on the nipple whereby it remains in place thereon, and retains plate 14 in position, when the housing 5 is tilted up. In operation, the propeller housing 5 is held and firmly seated against the packing 17 by the propeller thrust which forces it against the plate 14 and expands it radially both outward and inward so as to provide a good seal both around the nipple 12 and between the sides of plate 14 and chamber 13 and the packing 17. The greater the propeller thrust, the more secure the seal. Since there is no fixed connection, the propeller housing 5 can be tilted up at any time, in which case of course the seal is broken, but immediately restored when the propeller housing swings back into its normal operating condition. Since transfer of exhaust gas and cooling water between the engine in the boat and the passages in the outboard leg is not normally required when the leg is tilted for any substantial period of time,

since the engine will then normally be shut down, and since a brief interruption of such transfer, such as when the leg tilts from contact with an underwater object, does not injure the engine, such interruption is not important.

If it is desired that only One connection be made between one pipe 11 and one chamber 13, the packing 17 may be in the form of a simple ring or washer and additional setscrews 16 may be provided to maintain plate 14 in a position parallel to surface 24 when the leg is in normal operative position. If it is desired to use the sealing arrangement for two or more fluid pipe connections, such as for cooling water and exhaust gases, then the packing 17 may take the form of a pad having two or more pipe nipple openings therein. When this sealing arrangement is to be used for two pipe connections between the boat and the propeller housing, the same plate 14 and packing 17 as described above may be employed, the nipple 12 in the exhaust line being advantageously placed on one side of the setscrew 16 and the cooling water intake 18 on the other side, as shown in FIG. 2. The plate 14, preferably, has the same configuration as the pad, except that the plate has slightly larger clearance holes for the nipples 12 and 18. As the leg swings down against the pad 17, plate 14 rocks on the engagement between stop member 15 and setscrew 16 and automatically becomes aligned in a position substantially parallel to surface 24. The pressure on the pad 17 exerted between surface 24 and plate 14 during normal forward propulsion of the boat is, accordingly, generally uniformly distributed throughout the area of the pad.

While only a certain preferred embodiment of this invention has been shown and described by way of illustration, many modifications will occur to those skilled in the art and it is, therefore, desired that it be understood that it is intended in the appended claims to cover all such modifications as fall within the true spirit and scope of this invention.

What is claimed as new and what it is desired to secure by Letters Patent of the United States is:

1. In a drive unit for a boat including a power leg and means hingedly connecting said leg for tilting with respect to the boat, whereby the leg and boat comprise one and another assembled structure hingedly joined for pivoting with respect to each other, each said structure having a surface portion directed toward the other so disposed that said surfaces swing toward each other and swing apart as said leg swings respectively toward operating position and toward tilted position, each said structure comprising a fluid passageway, the combination of a pipe nipple communicating at one end with said passageway of one said structure, said nipple being fixed to said one structure and extending from said surface portion thereof toward said surface of the other structure and terminating in a free open end, a pad disposed around and carried by the nipple in a predetermined position spaced therealong from said free end thereof, said surface portion of said other structure being provided with an opening into its said fluid passageway aligned and proportioned loosely to receive said free end of said nipple thereinto when said surfaces swing toward each other while said surface portion of said other structure contacts said pad outwardly around said opening, and means fixed with respect to said one structure for retaining said pad against displacement from its said predetermined position in a direction away from its said free end.

2. The combination according to claim 1 wherein the means for retaining said pad comprises a plate surroundingly disposed on said nipple and adjustably positioned therealong with respect to said surface portion of said one structure.

3. The combination according to claim 1 wherein the pad is resilient and stretchedly engaged on said nipple.

4. The combination according to claim 2 wherein the position of the plate is determined by adjustable stop means extending between the said first structure and the plate and engaging a limited area of the plate whereby the plate may rock on said stop means into a position to distribute the compressive forces substantially uniformly on said pad when propulsion thrust urges said surface portions toward each other.

5. In a drive unit for a boat including a tilting power leg urged forward by normal forward propulsion thrust, a first part having an aperture therethrough, a hollow pipe nipple extending through said aperture and projecting from said part and terminating in a free open end, said pipe nipple having an opposite end provided with an opening into said nipple, a packing pad surrounding and carried by said nipple disposed between said free end and said first part, a second part having an opening loosely receiving said open end of said nipple thereinto when said leg is in normal operating position, one of said parts comprising a portion of said leg and the other said part being fixed with respect to said boat, said parts engaging forceably against opposite faces of said pad when said power leg is in normal operating position and is being so urged forward by propulsion thrust, said leg being provided with a fluid passage communicating with one of said openings and said boat being provided with a fluid passage communicating with the other of said openings, whereby, when said leg is in normal operating position and said pad is forceably engaged by said parts, said passages are in communication through said nipple and the connection between said nipple and said second part around the opening therein is sealed by said pad.

6. The combination according to claim 5 wherein said first part is fixed with respect to the boat and the second part comprises a portion of the leg.

7. The combination according to claim 5 wherein adjustable stop means are provided to retain said first part in fixed selectively adjustable relation along said nipple whereby to correspondingly adjust the trim of the power leg.

8. The combination according to claim 5 wherein the first part has a front surface for contacting said pad and a back surface opposite its said front surface, the passage communicating with the opening into said opposite end of said nipple is bounded by a partition having an exposed face disposed toward and spaced from said back surface, and adjustable means are provided to adjust the spacing between said face and said first part thereby to adjust the operating trim of said leg.

9. The combination according to claim 5 wherein said boat has a stern closure and said first part and said nipple are attached to the boat and disposed outwardly and aft of said stern closure.

10. The combination according to claim 9 wherein adjustable means are provided to adjust the spaced position of the part with respect to the stern closure into desired predetermined position, thereby to adjust the operating trim of the leg.

11. In a drive unit for a boat including a hull stern closure and a tiltable outboard power leg outwardly ad jacent said closure, a pipe nipple extending outwardly from said closure toward said power leg and terminating in a free open end, fluid conduit means in said boat communicating with the interior of said pipe nipple, said leg having a surface portion disposed toward said closure and provided with an opening therethrough communicating with an interior fluid passageway in said leg, said opening being positioned to receive said free end thereinto when said leg is in normal operative position thereby to establish fluid communication through said nipple between said conduit and passageway, a resilient sealing pad exteriorly disposed on said nipple spaced from said free end, said pad having a first face disposed toward said surface of said leg and having an opposite face disposed toward said stern closure, and means providing a backing against said opposite face in predetermined position with respect to said hull closure and cooperative with said surface to apply compressive force on said pad against said surface portion of said leg around said opening therein in re sponse to propulsive thrust of said leg during normal forward operation of the boat whereby the connection between said pipe nipple and said leg passageway is sealed by said pad.

12. The combination according to claim 11 wherein said leg surface portion and said backing are flat.

13. The combination according to claim 11 wherein means are provided to adjust the position of said backing means with respect to said hull closure thereby to adjust the operative trim of said leg.

14. The combination according to claim 11 wherein said backing means comprises a plate element surrounding said nipple, wherein an adjustable stop means is pro- References Cited UNITED STATES PATENTS 6/1954 Canazzi. 5/1960 Patty 115-41 X FOREIGN PATENTS 3/1942 France.

15 MILTON BUCHLER, Primary Examiner.

T. MAJOR, Assistant Examiner. 

